Like several other big First Amendment cases the Supreme Court will hear this year, Masterpiece Cakeshop is not really a First Amendment case. By its terms, the First Amendment restrains only “Congress” from making laws abridging “the freedom of speech” or prohibiting “the free exercise” of religion, but the Masterpiece case involves a state law. It is the Fourteenth Amendment, adopted after the Civil War, that restricts the states’ powers over religion or speech. Yet, as in last year’s Trinity Lutheran case, the Fourteenth Amendment has barely been mentioned in the briefing so far.

Our amicus brief to the Court in Masterpiece Cakeshop is so far the only attempt to consider at length the relevance of the original meaning of the Fourteenth Amendment for the case. Our scholarly work has documented in detail—sometimes quite tedious detail!—that the original meaning expressed by “privileges or immunities of citizens of the United States,” which the Fourteenth Amendment guaranteed the freedmen, includes civic equality with all similarly situated fellow citizens of the United States. Although it is fuzzy at the margins, the authors of the amendment made its central applications very clear, especially in the Civil Rights Acts of 1866, 1871, and 1875 and in the discussions leading to them. In particular, they made clear that the Fourteenth Amendment forbids not only racial discrimination, but also creedal discrimination—giving fewer rights to some citizens because of their religious or political beliefs. In many ways, to be sure, hostility to creedal discrimination resonates with current First Amendment speech and religion doctrine. When states are involved, however, originalist interpretation can and should stand on its own Fourteenth Amendment foundation of equal citizenship….

In sum, the common law and the original Republican understanding of the Fourteenth Amendment converge on the same intuitive argument in favor of Masterpiece Cakeshop: America is an inclusive republic, where all citizens, regardless of race, color, creed, or way of life, have a right to participate in the marketplace, free from the creedal exclusions imposed by those armed with state coercive power, save perhaps where that citizen uses some monopoly power to exclude other citizens from the market. Colorado has sought to force the baker either to leave his profession or provide wedding-related services incompatible with his creed. He can have no duty to provide such services where the same-sex couple can obtain their wedding cake a short distance down the street. Jack Phillips has no market power over dissenting minorities like that exercised in the Jim Crow South; he himself is the member of a dissenting creedal minority who seeks simply the liberty to participate in the market consistently with his conscience. When substitute goods and services are readily available, there is no moral, common-law, or Fourteenth Amendment justification for creedal and exclusionary limits on occupational freedom.